Friction laminate and disk assembly

ABSTRACT

A friction disk assembly includes a driven annular member having a plurality of radially extending torque transmitting support segments circumferentially spaced, each support segment defining an opening and supporting a friction laminate member across the opening. Each laminate includes a single backing plate which incorporates a pair of friction pads bonded to each of the opposed sides of the single backing plate. In a preferred form, the backing plate includes an offset portion which extends into the opening of an associated support segment, wherein an interference fit with the opening is established with respect to the offset portion in order to avoid relative movement between the laminate and the support segment under circumferential friction loads.

BACKGROUND OF THE INVENTION

This invention relates generally to the design of friction elementsutilized in driven disks of dry friction clutches. More particularly,the invention relates to the arrangement and structural characteristicsof friction elements adapted for installation in such disks.

In most modern day clutch systems, modular forms of construction areemployed in friction element design, wherein such elements arepre-assembled and secured by riveting to driven disk assemblies. Mostopposed sets of friction elements include at least two backing plates,wherein each plate carries a single friction element. Emphases in thenew modular construction processes are always on efforts to utilizefewer process steps and fewer numbers of parts, all in an effort toreduce costs. To the extent that laminations and lamination processeshave been improved over the years, an improved system would provide amodular one-piece friction element wherein backing plate and frictionelement parts are entirely laminated together as a single unit.

SUMMARY OF THE INVENTION

The friction laminate and disk assembly of this invention includes aplurality of friction laminate members each disposed rigidly over one ofa plurality of support segment openings in the assembly. Each laminatecomprises a single backing plate having a pair of opposed sides, whereinone of a pair of friction pads is each bonded to one of the opposedsides of the single backing plate. In one preferred form, the singlebacking plate includes an offset portion which extends into the openingof an associated support segment under an interference fit with at leasta portion of the boundary of the opening. In this manner, the laminateis capable of accommodating significant circumferential friction loadswithout undergoing relative movement with respect to the supportsegment. The latter measure significantly improves the load-carryingability of the friction element over systems which rely entirely onshear load capacities of rivets employed to affix backing plates tosupport segments.

BRIEF DESCRIPTION OF INVENTION

FIG. 1 is a side view of a friction disk assembly which incorporates apreferred embodiment of the friction laminate of the present invention.

FIG. 2 is a fragmentary view of a friction element support segment ofthe clutch driven disk of FIG. 1, shown without the friction laminateincorporated therein.

FIG. 3 is a view along lines 3--3 of FIG. 1, showing a cross sectionalview of a friction laminate affixed by rivets to a support segment.

FIG. 4 is an alternate embodiment of the friction laminate of thepresent invention, as would also be viewed along lines 3--3 in lieu ofthe view shown in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring initially to FIG. 1, a clutch driven disk 10 is shown apartfrom a friction clutch (not shown) in which it is designed to operate.The driven disk 10 includes three circumferentially spaced frictionelement support segments 12 which extend radially from central diskportion 14. The disk portion 14 is secured by a set of rivets 16 to asplined hub 18. The hub, in turn, is designed for coupling to a splinedengine propshaft (not shown).

Each of the friction element support segments 12 contains a frictionlaminate or pad assembly 20, which includes a pair of opposed frictionelements or pads 22. Referring momentarily to FIG. 3, each friction pad22 includes a radially extending friction surface 24, which is parallelto an identical counterpart surface 24 on the opposite pad 22. Thus,each laminate assembly 20 contains a pair of pads 22 secured on oppositesides of a singular backing plate 30, the latter of which is affixed byrivets 46 to one of the three support segments 12. Each of the rivets 46will pass through an aperture 52 in one of the support segments 12 forsecuring a friction pad assembly 20 to a particular support segment 12.

It will be appreciated by those skilled in the art that the use of asingle backing plate 30 will require the inclusion of an aperture 40(FIG. 2) for permitting the singular backing plate to contain bothfriction pads having opposed friction surfaces 24. Thus referring nowmore generally to FIG. 3, one preferred embodiment is shown wherein thebacking plate 30 contains an axially or transversely offset portion 34.As will be seen from the cross-sectional end view of FIG. 3, the supportsegment 12 lies in a plane A--A as shown. The portion of the backingplate 30 which is secured to the support segment 12 by rivets 46,however, passes through a plane B--B parallel to that of the supportsegment 12. To the extent that the offset portion 34 of the backingplate 30 will, however, have its center in the same plane as that of thesupport segment 12, the pads 22 will have equal thicknesses as shown. Inthe same embodiment, it is also a feature of the present invention thatthe boundary 42 of the axially offset portion 34 will preferably engage,under an interference fit, the edge or boundary 32, at least in part, ofthe support segment aperture 40. This will assure against any relativecircumferential or transverse movement between the friction laminate orpad assembly 20 and the support segment 12. Otherwise, the rivets 46would be forced to carry all of the circumferentially applied frictionloads on the assemblies 20, and over a period time rivets tend to becomeelongated and permit looseness.

A second preferred embodiment, shown in FIG. 4, does not have an axiallyoffset portion 34 as does that of FIG. 3. Instead, the friction padassembly 20' has an entirely flat backing plate which lies fully withina plane B'--B', parallel to a plane A'--A' passing through the center ofthe support segment 12'. In the latter embodiment, axially extendingtabs 36 are utilized to engage the radial boundaries 32' of aperture 40'to provide an interference fit between the backing plate and the supportsegment. This form of the invention operates in the same manner as theinterference fit between the boundary 42 of the offset portion 34 andthe boundary 32 of the aperture 40 in the version of FIG. 3. However, itwill be noted that in the latter embodiment it will be necessary toutilize a pair of friction pads 22 having differing thicknesses. Asshown in FIG. 4, the lower pad 22' has a thickness which must be equalto the thickness of the upper pad plus the thickness of the supportsegment in order for the friction surfaces 24' to be, as is preferable,equidistant from the plane A'--A.

One preferred material for manufacture of the friction pad is acopper-base powered metal, of approximately eighty percent copper. Thelatter provides a superior heatsink capacity. The backing plate ispreferably formed of a copper plated steel (having a plating thicknessof 3 to 4 ten thousandths of an inch) to which the friction pads aresintered via the use of a copper-flux paste an adhesive bonding agent,at approximately 1700° F. In the preferred form of the invention, thetolerance range between either the support segment opening boundary 32and the associated offset boundary 42 or the tab 36 is approximately 1to 3 thousands of an inch maximum. This will provide an interference fitnecessary to assure rigid transverse securement.

Although only two preferred embodiments have been described and detailedherein, the following claims are envisioned to cover numerous otherembodiments which may fall within the spirit and scope thereof.

What is claimed is:
 1. A friction disk assembly adapted for use in afriction clutch, said disk assembly comprising a driven annular memberhaving a plurality of circumferentially and uniformly spaced torquetransmitting support segments, each segment containing an opening, afriction laminate member disposed rigidly across each opening, eachlaminate comprising a single backing plate having a pair of opposedsides, a pair of friction pads each bonded to one of said opposed sidesof said single backing plate, each pad containing an exposed frictionsurface, wherein said backing plate is affixed to one side of onesupport segment, and wherein said backing plate includes tabs whichextend against the boundary of said opening in one of said segments toprovide an interference fit between said laminate and said segment toavoid relative movement between said laminate and said segment undercircumferentially applied friction loads, and wherein, except for saidtabs, said backing plate lies entirely in a plane parallel and separatefrom a plane which passes through the center of said support segment. 2.The friction disk assembly of claim 1 wherein said opposed friction padsare of non-equal thicknesses, the first pad being on the side to whichsaid backing plate is affixed and being of lessor thickness than thesecond pad, wherein the exposed friction surface of each pad lies withina plane substantially equidistant from said plane which passes throughthe center of said support segment to which said plate is affixed.
 3. Ina friction disk assembly adapted for use in a friction clutch, saidassembly comprising a driven annular member having a plurality ofradially extended torque transmitting support segments circumferentiallyand uniformly spaced apart, each segment defining an opening; animprovement comprising: a friction laminate member disposed rigidlyacross each segment opening, each laminate comprising a single backingplate having a pair of opposed sides, a pair of friction pads eachbonded to one of said opposed sides of said single backing plate,wherein said backing plate of each laminate is riveted to one supportsegment, said backing plate of each laminate being affixed against onlyone side of said support segment, said backing plate defining an offsetwhich extends into the opening of said one support segment and definingan interference fit with said opening over at least a portion of saidopening, whereby each laminate may accommodate circumferentially appliedfriction loads without relative movement between said laminate and saidsupport segment.